What is PABX (Private Automated Branch Exchange)?

This page discusses PABX which is a telephone switching system, a server that works automatically. Originally it was called PBX (Private Branch Exchange). Nowadays almost all Private Branch Exchanges are automated, that is why we call them PABX. If you read on, you can get to know the types of PBXs and their roles.

The PABX allows and controls the sharing of different phone lines between different communication devices. The channel between the devices are built up by SIP (Session Initiation Protocol) (Figure 1). It is centralized around a local nework and may not need to be connected to a public phone network. PABX is usually used by call centers. The system provides callers a single access to multiple lines.

what is pabx
Figure 1 - What is PABX?


The PBX serves as a switching station for phone systems. Within an organization it connects phones and it can also connects them to PSTN (Public Switched Telephone Network). The server handles both the incoming and outgoing calls. Nowadays PBXs are automated, that means it selects lines automatically, there is no need to handle them manually. Its advantages are for example the flexibility and easy setup.

PBX uses a so called dial plan which is an individual digit code.

There Are Four Kinds of PBX Servers:
  1. Analog PBX (The voice signal is not digitalised.)
  2. Digital (The voice signal is digitalised.)
  3. IP PBX/VoIP PBX (Transmits voice signals via IP network.)
  4. Hybrid (It has both digital and IP PBX features.)

The latest type of this kind of system is the VoIP PBX/ IP PBX (Telephone system, also used for call-switching).

The Roles of PBX

  • establishes connections between users
  • preserve connection
  • disconnects calls
  • gives an account on statistics etc.

Since Ozeki Phone System is a pbx telephone system, it has many interesting and useful features that a telephone system can provide. Ozeki Phone System is a powerful and advanced system that is a good solution for businesses for handling calls.

Read through other pages that are related to PABX:

If you became interested in this topic, please watch our video:

What is PABX? (Video tutorial)

More information